Continue filling out your lecture outline for Chapter 5 for the following:
II  Where do lipids come from?

Plants make triglycerides and phospholipids from fragments of glucose.  Plants make sterols, but do NOT make cholesterol because they don't need cholesterol.  They need sterols, just not cholesterol.

Animals make triglycerides from fragments of carbohydrates, proteins or fats.  Animals can make cholesterol from saturated fatty acids, and carbohydrates.  Humans make all of the fatty acids they need except 2 called the EFAs (essential fatty acids).

Can you remember from the first part of this lecture which of the following are considered EFAS?

Click here if Linoleic is an EFA.

Click here if Linolenic is and EFA.

Click here if EPA and DHA are EFAs.

Look at the following drawings and notice that both of them are combinations of carbon, hydrogen and oxygen atoms.  As I said, both plants and animals (including us) can make fat (triglycerides) from fragments of glucose.



A TRIGLYCERIDE
GLUCOSE




Watch the following video to fill in your lecture outline on lipoproteins.


The following is a link to the above video:  https://www.youtube.com/watch?v=NBpLBWga-AA


 

Why are LDLs referred to as "bad" cholesterol, and HDLs referred to as "good" cholesterol?

LDL carries cholesterol from the liver to cells, and can contribute to plaque buildup in arterial walls which is why it is often referred to as "bad" cholesterol.

HDL carries cholesterol from cells to the liver for disposal, which is why it is often referred to as "good" cholesterol. 

The TRUTH is that there is no such thing as "good" or "bad" cholesterol.  There is only one type of cholesterol in both foods and in the body.  It is whether cholesterol is associated with LDL or HDL that makes it "good" or "bad".

Also you do not find LDL or HDL in foods, but the foods you eat can impact their levels.  Can you remember which fats increase LDL levels?

Click here if you think it is saturated and trans fat.

Click here if you think it is unsaturated fat.

 
IV  Recommendations regarding lipids & heart health
  1. Enjoy your food.
  2. Focus on nutrient dense foods.
  3. Dietary Guidelines 2015 Summary

    Keep total fat intake between 25-35 percent of Calories, mostly from WHOLE foods that provide unsaturated fats such as: nuts, seeds, avocado, olives, fatty fish

    Keep saturated less than 10% of Calories,  and trans fat as low as possible.

    According to the 2015 DGA report, "Strong and consistent evidence shows that replacing saturated fats with unsaturated fats, especially polyunsaturated fats, is associated with reduced blood levels of total cholesterol and of low-density lipoprotein-cholesterol (LDL-cholesterol). Additionally, strong and consistent evidence shows that replacing saturated fats with polyunsaturated fats is associated with a reduced risk of CVD events (heart attacks) and CVD-related deaths.

    Some evidence has shown that replacing saturated fats with plant sources of monounsaturated fats, such as olive oil and nuts, may be associated with a reduced risk of CVD. However, the evidence base for monounsaturated fats is not as strong as the evidence base for replacement with polyunsaturated fats. Evidence has also shown that replacing saturated fats with carbohydrates reduces blood levels of total and LDL-cholesterol, but increases blood levels of triglycerides and reduces high-density lipoprotein-cholesterol (HDL-cholesterol). Replacing total fat or saturated fats with carbohydrates is not associated with reduced risk of CVD. Additional research is needed to determine whether this relationship is consistent across categories of carbohydrates (e.g., whole versus refined grains; intrinsic versus added sugars), as they may have different associations with various health outcomes. Therefore, saturated fats in the diet should be replaced with polyunsaturated and monounsaturated fats."

    The new 2015 guidelines dropped the limit on consumption of dietary cholesterol to 300 mg per day, but the new guidelines note that “this change does not suggest that dietary cholesterol is no longer important to consider when building healthy eating patterns. As recommended by the IOM, individuals should eat as little dietary cholesterol as possible while consuming a healthy eating pattern.”

    8 oz.  of seafood per week. 

     

  4.   Nutritional disadvantages of a low fat diet.
    1. hard to get enough  EFAs (essential fatty acids)
    2. hard to get enough vitamin E
    3. may increase LDL and lower HDL (and that's the opposite of what is heart healthy)
 
 
Looking at the table of foods in your lecture outline, and deciding which would be most likely to raise your risk of heart disease, hopefully you decided on the hamburger.

Saturated fat in the diet usually has a bigger impact on someone's risk of heart disease than does the actual cholesterol in the diet, because when you take in more dietary cholesterol the body synthesizes less. The saturated fat is used by the body to make cholesterol, and it also impacts increasing LDL levels which can contribute to plaque along artery walls and obstruct blood flow.  



Something that can contribute to the obstruction is damage to the lining of the blood vessels, which can happen due to a variety of reasons, including smoking and stress.  When the lining of the heart artery is damaged, small blood particles called platelets accumulate causing reduced blood flow which can then lead to a heart attack.



The Harvard Mental Health Letter says that people with a set of traits known as the Type D (“distressed”) personality suffer from a high degree of emotional distress, but they consciously suppress their feelings.


END OF LECTURE 5A.  
Now you're ready for LECTURE 5B.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Correct Linoleic and Linolenic fatty acids are considered essential fatty acids (EFA's).

Click Here to return to Lecture.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Incorrect. EPA and DHA are not considered essential fatty acids (EFAs).  They can be synthesized from linolenic.

Click here to return to lecture.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Correct.  Both saturated and trans fat can increase LDL levels.

Click here to return to Lecture.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Incorrect.  Unsaturated fats actually lower LDL levels.

Click here to return to lecture.